Blue Line Complete 72cc High-Performance Big Bore Cylinder Kit for 50cc 4-stroke 139QMB engines.

Original Parts For Scooters SKU 151-280-47mm

NOTE: Before ordering, remove the valve from your scooter's head and measure the full length of the valve stem. This kit works with 64mm valves. If your scooter has 69mm valves, you'll need the following 69mm big bore kit.

Pump up that weak engine to a respectable 72cc displacement, on a budget. This kit is not intended to make your scoot a screaming race machine. It is intended to get you that extra power you need. (Most Chinese 50cc's only put down around 1.5hp to the ground.)

Specifications:

• 1 - Head Assembly with 64mm valves
• 1 - Iron Cylinder with 47mm bore
• 1 - Piston with Rings (Not Pictured)
• 1 - Wrist Pin 
• 2 - Circlips
• 2 - Exhaust studs
• 2 - Intake Studs
• 1 - Base Gasket
• 1 - Head Gasket

Compatibility:

139QMB-based 50cc / 80cc engines with the following engine codes:

Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.

About Blue Line: Blue Line offers OEM equivalent replacement parts for on-road scooters. Blue Line parts are a direct-fit replacement when OEM parts are unavailable or overly expensive for your scooter. Since 2018, Blue Line has provided quality parts at great prices.